It is known to connect MEMS switches to form a switching array, such as series connected modules of parallel switches, and parallel connected modules of series switches. An array of switches may be needed because a single MEMS switch may not be capable of either conducting enough current, and/or holding off enough voltage, as may be required in a given switching application.
An important property of such switching arrays is the way in which each of the switches contributes to the overall voltage and current rating of the array. Ideally, the current rating of the array should be equal to the current rating of a single switch times the number of parallel branches of switches, for any number of parallel branches. Such an array would be said to be current scaleable. Current scaling has been achieved in practical switching arrays but voltage scaling has not.
In concept, the voltage rating of the array should be equal to the voltage rating of a single switch times the number of switches in series. However, achieving voltage scaling in practical switching arrays has presented difficulties. For instance, in known switching arrays for a given voltage rating of a switching module, it is not possible to continue to increment the number of switching modules that may be connected in series to achieve any desired voltage rating. This is due to the fact that the voltage rating of the circuitry in a respective switching module will eventually be exceeded due to relatively large voltage levels that can develop across the open switches. Thus, known switching arrays are limited in the number of switches that can be interconnected in series, and consequently lack the ability to provide voltage scalability.